The villain's stats are 8/4/73, and all the rest of 24 stats that my HUD displays are literally zero

Is it fine to 2nd barrel him on this board? I give him some pockets in his calling range. He will miss often. He might call the flop with a medium pair, but after the king showed up, I thought that he either has a set or he will fold.

Rocks are pretty bluffable, aren't they? He is short though, so I really don't know.

Also, what about bet-sizing? 1/2 the pot is fine to bluff into one opponent on a dry board?